What does CAS number mean? A comprehensive analysis of the chemical industry’s “identity cards”
In the chemical industry, we often come across the term CAS number, which is a key identifier in product specifications, chemical databases and daily operations. Whether in product specifications, chemical databases, or in the daily operations of chemical companies, the CAS number is a key identifier.What does CAS number mean? This article will give you a detailed answer.
What is CAS number?
CAS number (Chemical Abstracts Service Number) is a unique identifier assigned by the Chemical Abstracts Service (CAS). Each chemical substance, whether naturally occurring or synthetic, has a unique CAS number, which allows them to be accurately identified and traced worldwide.
Structure and characteristics of the CAS number
The CAS number usually consists of three parts of numbers, for example 64-17-5, which represent different information:

The first part, which can vary from two to seven digits, identifies a unique number for the chemical substance;
The second part is always a two-digit number, which is used to calibrate the first part;
the third part is a single check digit, which is used to verify the correctness of the first two parts of the number.

This structure allows CAS numbers to avoid duplication and provides a standardised way to identify chemical substances.
The Uses and Importance of CAS Numbers
Once we understand what a CAS number means, we also need to understand what it is actually used for. the main purpose of a CAS number is to ensure that a chemical substance is unique and globally recognised. Since chemical substances may have multiple names and aliases, the use of a CAS number avoids confusion. For example, Ethanol may be called alcohol, ethyl alcohol, etc. in different contexts, but their CAS number 64-17-5 is unique, which ensures that there is no misunderstanding when communicating between different languages and regions.
CAS numbers play a vital role in purchasing, marketing, research and regulatory management in the chemical industry. For example, in Safety Data Sheets (SDS), CAS numbers are used to clearly identify the chemical substances involved so that interested parties know exactly what the substance’s properties and potential risks are.
Obtaining and Querying CAS Numbers
If you want to look up the CAS number of a chemical substance, you can search through several online chemical databases, such as the CAS Registry, PubChem, and others. These databases provide a wealth of information on chemical substances, including their CAS numbers, molecular structures, chemical properties, and more.
For companies, having accurate CAS numbers not only helps compliance management, but also improves the efficiency of supply chain management. For example, ensuring that the raw materials procured are exactly the same as the chemical substances required to avoid quality issues or regulatory risks.
Conclusion
The answer to the question of what a CAS number means goes beyond its literal meaning to its irreplaceable role in the chemical industry, where it acts as an ‘identity card’ for chemical substances, ensuring their accurate identification and management on a global scale. Understanding and correctly using CAS numbers is an essential skill for those working in the chemical industry.